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Testimony, induction andfolk psychologyJack Lyons aa University of ArizonaPublished online: 02 Jun 2006.

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Australasian Journal of Philosophy Vol. 75, No. 2; June 1997

TESTIMONY, INDUCTION AND FOLK PSYCHOLOGY

Jack Lyons

I. Introduction

There is widespread agreement among epistemologists that our testimonial beliefs

(beliefs held on the basis of testimony) are generally justified. Most also agree that testi-

mony is responsible for a vast portion of what we know. The controversy concerns how

or why testimonial beliefs are justified. Is the justification of testimonial belief in some

sense basic, or is this justification parasitic on more fundamental justificational princi-

ples regarding, e.g., perception and induction?

Although the latter position has an intuitive pull and has traditionally been the domi-

nant theory, it has come under a good deal of attack lately. I want to argue here that at

least some of this attack is unsuccessful. In C.A.J. Coady's important recent book on tes-

timony [2], he argues at length against the idea that our justification for believing

testimony can be reduced to inductive justification. According to an inductivist theory of

testimonial justification (henceforth simply 'inductivism'), testimonial justification is

just a special case of inductive justification; testimonial beliefs are justified because first-

hand experience gives us inductive evidence for the claim that people are generally

accurate in their reports. ~ Coady takes Hume to be the classical advocate of this position

(which he calls 'reductivism', since it attempts to reduce testimonial justification to a

kind or kinds of justification more basic), and he insists that the inductivist theory is

doomed to failure for a number of reasons.

My goal here is to show that Coady's arguments against this roughly Humean project

fail, and that while the particular inductivist theory advocated by Hume has some short-

comings, certain modifications of this theory produce a far more tenable version of

inductivism. In sections II-IV I will address three main arguments that Coady offers to

show that induction cannot justify our testimonial beliefs. Not only do I think that there

are serious problems with each of these arguments, but I think that the nature of these

problems suggests a way in which an inductivist might go about making a positive pro-

posal. In the remainder of the paper I offer a rough sketch of how that proposal might

look and argue that our natural folk psychological abilities can and should be taken into

consideration in an explanation of how our testimonial beliefs are justified. In the end, I

will argue that at least one theory concerning the nature of our folk psychological beliefs

provides a strong argument in favour of inductivism.

I should begin with an important procedural point. I take the project at hand to be one

of explaining how it is that normal people are justified in their testimonial beliefs. 2 This

' By 'inductive', I simply mean to capture all those cases of reasoning that are not deductive. Thus, unlike, e.g., Elliot Sober [ 11 ], I will consider abduction (i.e., inference to the best explana- tion) to be a species of induction.

2 I do not take the present project to be one of endorsing either internalism or externalism. A relia- bilist, for example, might very well be interested in reducing the reliability of testimony to the more basic reliability of induction.

163

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164 Testimony, Induction and Folk Psychology

means (i) that I will be presupposing that people are generally justified in their testimoni-

al beliefs and that they are justified in roughly those beliefs that they think they are, and

(ii) that the project at hand is not to convince the reader that testimony (often) produces

justified beliefs, but to explain why agents who form beliefs on the basis of testimony are

(often) justified. For this sort of epistemological project, the reasonings or other psycho-

logical processes that render reliance on testimony justif ied must be the kinds of

processes that normal people actually employ or at least approximate? Furthermore, I

take it that the issue concerns only the original justification of such beliefs, thus avoiding

contention about whether memory produces or merely preserves justification.

Coady has three main arguments against the roughly Humean project of inductivism:

(1) The individual simply doesn't have enough non-testimonial information at her

disposal to justify the relevant inductive inferences - very little of what we (hear-

ers) have heard testified have we had the opportunity or even the ability to

personally corroborate. [2, pp. 82-85]

(2) The whole inductivist approach is deeply flawed, because if testimony were not

to some extent reliable, there would be no such thing as testimony. [2, pp. 85 ff]

(3) We cannot learn or understand a language without supposing that the speakers

of the language are telling the truth much of the time. [2, ch. 9]

Each of these arguments will require a considerable amount of unpacking; I will deal

with them in reverse order.

II. Truth and Language Acquisition

Thomas Reid was, as far as I know, the first to claim that we could not learn a language

if we did not believe that others usually spoke the truth [10, p. 196]. Since we do in fact

learn languages, Reid concludes that we must have some sort of innate bias that causes

us to believe that people are telling the truth, a psychological tendency which he calls a

'Principle of Credulity'. Coady's argument (3) invokes a Davidsonian version of this

claim: a hearer cannot interpret others without presuming that much of what they say is

true, i.e., radical interpretation requires a presumption of speakers' veracity. This argu-

ment is not aimed directly at what I am calling inductivism, since Coady takes the

argument to be general enough to cut against any theory that takes a basically reductivist

tack. In the next section I will address the uses to which Coady wants to put this and the

related argument (2) against inductivism in particular, but first I would like to make a

preemptive case for the claim that the Principle of Credulity and similar principles have

nothing to say directly on the subject of whether testimonial beliefs are inductively justi-

fied.

The notion of approximation is far less clear than many authors seem to think. However, I take it that there is an intuitive sense in which people instantiate or approximate the statistical syllo- gism, for example, while there is no such sense in which people approximate certain rules of probability, like believing all necessary truths to the degree of 1. This rough, intuitive notion will have to suffice for the present paper.

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Jack Lyons 165

Suppose children are born with the Principle of Credulity. What should we expect

this to tell us about the justifications of our linguistic beliefs (beliefs about the meanings

of words and so forth)? There are two ways to go here. The first is to claim that if Reid's 'Principle' is really innate, then it is responsible for justifying the beliefs that it produces. The second (and more interesting because less often noticed) approach is to claim that

the principle is only essential in that it gives u san innate bias, without which we simply

would not have the inferential power to learn a language. The standard view in language

acquisition has it that in learning language, children (at least tacitly) formulate and test

hypotheses, and certain innate biases serve to constrain the number and nature of

hypotheses that can be formulated. What is responsible for the formulation of the

hypotheses, however, need not be what is responsible for the later justification in accept-

ing or retaining any given hypothesis. It is quite reasonable to claim that what justifies

this acceptance is the ability of the hypothesis to survive potentially falsifying evidence and to account for the relevant data.

So there are two distinct procedures at issue here, hypothesis formulation and hypoth- esis testing. Although the former may be a sine qua non for language learning, it may

still be the latter that justifies my beliefs about my language. The bias toward believing

what people say is causally necessary for my justified belief about what their words mean, but this causal responsibility does not imply justificational responsibility - the principle is required for the existence, but not the justification, of the relevant beliefs. In

the same vein, the child's innate assumptions about the possible syntactic structures of

natural languages are required for understanding a language, but these assumptions play

no interesting role in justifying any beliefs about the language. If the preceding account is right, then nativism about a Principle of Credulity and

inductivism about testimonial justification are orthogonal. The hypothesis of general

veracity combined with hypotheses about the meanings of utterances generally with-

stands falsification (people do not usually say something that I think means or implies

that the dog is in the room when I think that the dog is not in the room), provides useful

predictions (when people say something that I think means that the dog is in the other

room, and I go to find the dog, it is usually there), and in a general way, accounts for why these people are making these incessant noises. So much for the preemptive argu- ment about the irrelevance of the Principle of Credulity to whether testimony is justified inductively or not. The general moral is that the innateness of a faculty without which we

could not have certain beliefs, still allows for the possibility that the beliefs produced by

that faculty are justified inductively (abductively, to be more precise about the current

case). I will next deal with the more specific arguments that Coady levels against induc-

tivism.

III. Reliability Presupposed?

Coady's argument (2), like his (3), maintains that there is a fundamental flaw in the

Humean project of relying on merely first-hand experience to check the reliability of tes- timony, for we could not check the reliability of testimony if we were not able to first

detect instances of testimony. But the very detection of testimony presupposes the relia- bility of testimony.

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166 Testimony, Induction and Folk Psychology

This difficulty consists in the fact that the whole enterprise of [ inductivism]

requires that we understand what testimony is independently of knowing that it is,

in any degree, a reliable form of evidence about the way the world is. This is, of

course, the point of Hume's saying: 'The reason why we place any credit in wit-

nesses and historians, is not derived from any connexion, which we perceive a

priori, between testimony and reality, but because we are accustomed to find a

conformity between them.' It is a clear implication from this that we might have

discovered (though in fact we did not) that there was no conformity at all between

testimony and reality. [2, p. 85]

Coady then goes on to argue that this 'clear implication' of Hume 's theory is, in fact,

false; we could not possibly have discovered a total lack of conformity between truth and

testimony. In such a case, he claims, there would be no such thing as the speech-act of

testifying, and no utterances would have any discernible content. So, by modus tollens,

Hume's theory is false.

There are a number of problems with this line of argumentation. For the moment, let

us grant to Coady that there is some sort of a necessary connection between truth and tes-

t imony (qua testimony) - i.e., that it is impossible that there be test imony yet it be

completely inaccurate. 4 Does Hume's theory imply the negation of this claim? No. Hume

is careful not to claim that there is no necessary connection between truth and testimony,

only that it is not the case that we believe witnesses because of such a connection, since

we are not aware of any such connect ion: Not only is Hume 's claim very likely true,

given that most people have never considered the issue, but the fact that we do not rea-

son on the basis of a perceived necessary connection does not even begin to imply that

there is no necessary connection. And even if Hume had made the stronger claim, there

is no reason to think that this would be a central tenet of the inductivist position. It might

very well be the case that testimony has all sorts of interesting properties that have noth-

ing to do with its role in the justification of beliefs.

Perhaps Coady thinks that having inductive evidence for p implies that p is contin-

gent. But surely it is possible to measure a number of r ight t r iangles and acquire

inductive evidence for the truth of the Pythagorean theorem, or to gather empirical (and

similarly inductive) evidence for an approximation of n. Hence, it cannot be a general

rule that induction implies contingency.

Does the inductivist project presuppose the reliability of testimony? In the previous

section, I described how an inductivist theory might explain children's learning of a lan-

guage. This, I take it, is part of the inductivist project, to describe how children acquire

justified beliefs about the noises that they hear people making. As argued in the last sec-

tion, abduction can explain how listeners come to have justified beliefs that the noises

This claim cannot be that there is a necessary connection between the way the world is and the noises we hear people make (at least not any interesting one). Hume's caution, of course, is not the result of his having noticed any sort of necessary connec- tion. It is more likely a simple consequence of his general tendency to refrain from making explicit metaphysical claims and to focus instead on psychological and epistemic ones. Similarly, in his famous discussion of causation, Hume is careful never to deny the existence of any necessary connection between cause and effect; he merely denies awareness of such a con- nection.

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Jack Lyons 167

other people are making are both meaningful and (often) true. There is no legitimate rea-

son to insist that these two be handled serially, that first we discover the meaning then

the reliability. The inferential process I am offering here is abduction after all, and there

is nothing strange about having a set of hypotheses be the unit of testing where abduction

is concerned, since it is normally only sets of hypotheses that make clear predictions.

Thus, it is entirely possible that children acquire some evidence for the reliability of tes-

timony at the very same time that they learn the language. This, however, is quite

different from presupposing the reliability of testimony.

Thus, I think that this phase of Coady's attack against the Humean project is unsuc-

cessful. It is probably true that if there were no correlation at all between testimony and

the way the world is, then we would not be justified in our testimonial beliefs - that is,

we would not be justified in thinking that there were such a correlation. But I presume

likewise that i f it were not the case that most people do not have three legs, we would not

be justified in our belief that they do not. Such counterfactuals are not indications of

what is inductively justified and what is not.

IV. Induction and the Paucity of Evidence Arguments

There is one more argument that Coady briefly mentions, and although he leans on this

one the least, we will see that it is really the hardest to reckon with. In addition to the

language-oriented arguments dealt with above, Coady argues that in order for induction

to justify our testimonial beliefs, we would need a much greater fund of direct, non-testi-

monial evidence about the world than we have:

• . . [I]t seems absurd to suggest that, individually, we have done anything like the

amount of field-work that [inductivism] requires. As mentioned earlier, many of

us have never seen a baby born, nor have most of us examined the circulation of

the blood nor the actual geography of the w o r l d . . . This list [is] supposed to be

typical in that it indicate[s] areas in which we rightly accept testimony without

ever having engaged in the sort of checking of reports against personal observa-

tion that [inductivism] demands. [2, pp. 82-83, emphasis in original]

The very fact that we rely on testimony for so much of what we believe indicates that we

have not done a lot of independent solitary observation. This provides what I will call the

Weak Paucity of Evidence Argument:

WPA: Most people have personally verified precious few reports, and this little bit

of first-hand observation is not enough to inductively determine the general relia-

bility of testimony. Any inductive argument for the reliability of testimony would

be an argument from too small a sample.

Although I want to return to this argument later, Coady considers a version of induc-

tivism that takes into account various kinds of reports, and against this theory he offers

two arguments that collectively I will call the Strong Paucity of Evidence Argument,

SPA:

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168 Testimony, Induction and Folk Psychology

(SPA i) For most of us, there are only a few kinds of reports that we might have

been able to verify personally. The rest will be completely without inductive sup-

port.

(SPA ii) Any given report can be classified in many different ways, only some of

which will yield inductive justification. But it is a problem for inductivism that

there is no principled level of generality at which to specify the different kinds of

reports.

The trouble with SPA, as I see it, is that it is too strong; I will argue that the assumptions

implicit in this two-pronged argument are sufficient to undermine induction in general.

Inductive inference has two main components: first, there is inductive generalization,

the process by which we come to form beliefs in statistical or universal generalizations. 6

In order, however, to apply the knowledge encoded in these generalizations to any par-

ticular case, we will have to engage in direct inference, the process by which we infer

definite (i.e., single-case) probabilities from the indefinite probabilit ies that we have

induced. (Definite probabilities are things like the probability that Brown is over six feet

tall, or the probability that my doing A at time t will lead to outcome 0. 7) Now the differ-

ence between WPA and SPA, in a rough and ready way, is that the first is concerned

with the size of the sample, while the latter is concerned with the representativeness of

the sample. But the problem that Coady raises in SPA is an extremely general one, for it

is the problem of the reference class for direct inference, not the problem of the reference

class for direct-inference-for-testimony. There is nothing in Coady ' s argument that

allows us to restrict the argument to testimony-related reference classes. Thus, if SPA

shows that induction is insufficient for justifying testimonial beliefs, it shows that induc-

tion is insufficient for just i fying any beliefs. Coady thinks it is a 'perhaps dubious

assumption' that this problem of the reference class can be solved, but the generality of

this problem indicates that it can be solved, if induction in general is any good. The solu-

tion is worth looking into.

The classical and intuitive solution to the problem of the reference class was given by

Reichenbach [9]: when trying to figure out the probability of some particular event, we

are to embed that event in the narrowest reference class for which we have adequate

probabilistic information. 8 Reichenbach 's principle serves an illustrative purpose; the

exact formulation of a theory of direct inference is not important here, but the assump-

tions underlying this epistemic principle are crucial to the current discussion. The first of

these assumptions is that we need not consider every reference class to which our target

6 Exactly what inductive generalization produces is somewhat controversial, but it will be irrele- vant to the present discussion whether it produces beliefs in precise probabilities, beliefs in ranges of probabilities, partial beliefs, degrees of belief, or what have you.

7 This terminology, which I borrow from John Pollock [8], helps to pinpoint a certain tension in this argument: the first part of the argument (SPA i) assumes that there is a principled method of classification for inductive generalization (such that we can have inductively justified beliefs about the reliability of some, but only some, kinds of reports), and then (SPA ii) proceeds to deny that there is any such principled method of classification available for direct inference. It is hard to see how they could both be true.

8 A more precise formulation of this view is found in [8], which endorses something very much like this and to which I owe much of the ensuing discussion.

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Jack Lyons 169

belongs. The second is that even some reference classes that we do consider can reason-

ably be ignored; my knowing that this object, c, is a C and that most Cs are Ds gives me

a reason to bel ieve that c is (probably) a D. This sort o f inference, o f course, is eminent ly

defeasible, but the knowledge that c is also an F does not, by itself, defeat my original

inference. Certainly C & F is a narrower reference class than C, but i f I do not know any-

thing about how many C&Fs are Ds, then I am just if ied in ignoring the fact that c is also

an F. Of course, i f I do know something about that probability, then I need to consider it,

but otherwise I do not?

Now it might be thought that we need some posit ive reason for thinking that any nar-

rower class is irrelevant in the sense that being an F, to continue with the above example,

does not change the probabili ty o f being a D given that it is a C. However , this require-

ment is too strong. First o f all, s ince any object falls into indefinitely many reference

classes narrower than the one we take to be relevant, we would have to have indefinitely

many just if ied beliefs in order ever to be just if ied in an inductive inference of this nature.

Second, consider a representat ive case: my insurance agent knows the statistics for dri-

vers o f my age, gender, and driving record in this state. Yet my agent also knows my

address, al though she does not have any statistics for drivers o f my age, gender and dri-

ving record who live at my address. H e n c e my insurance agent lacks any pos i t ive

evidence that my street corner is not a particularly dangerous one. Nor, I will assume, is

she so dull as to assume that this is irrelevant information. Some corners are more dan-

gerous than others. Does this mean that her bel ief about the approximate l ikelihood o f

my gett ing into an accident is unjustified, since she has not taken into consideration my

street comer? Presumably not. Certainly, she would be more just if ied if her bel ief were

founded on a greater amount of evidence (and hence would be just if ied in holding a less

tenuous bel ief and/or one that makes a more precise estimate o f the relevant probability),

but this does not imply that the less than fully informed bel ief is unjustified. If justifica-

tion required us to be fully informed, we would not need induction.

The Reichenbachian principle is not idiosyncratic to test imony, nor is it l imited to

direct inference. Induct ive general izat ion must rely for its just i f icat ion on something

quite similar; it seems clear that if all the swans I have ever seen are white, and all I

know about Australian swans is that there are some and that I have not seen them, I am

still just i f ied in my bel ief that all swans are white, despite the (unknown to me) fact that

Australian swans are black. What justif ies this inference appears to be the fact that there

is no narrower reference class about which I have any just i f ied beliefs and which offers

me any reason for retracting my inference. Similarly, if I have some inductive evidence

for the reliability of tes t imony in general, then I am just i f ied in thinking that you are

telling me the truth unless your present report falls into a narrower reference class f o r

which I have some positive reason to believe your testimony is unreliable. The fact that

There are cases that this sort of theory will not address. For example, suppose I know that c is a C and that c is an F, but I do not know the probability of c being a D given that it is a C&F, and I know that the probability of c being a D given that it is a C is different from the probability of it being a D given that it is an F. It is unclear what I should infer here, and as far as I know, no one has a neat solution to this problem. However, it should be somewhat clear by this point and more clear shortly, that this is everybody's problem, and to believe that induction is generally a justification-conferring procedure is to assume that there is some solution to this problem, even if no one has yet articulated it.

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170 Testimony, Induction and Folk Psychology

you have dark hair is irrelevant to whether I am justified in accepting your testimony,

because I do not have any information concerning the reliability of dark-haired people's

testimony. Nor do I have any reason to reject your claim that, say, ulcers are caused by

bacteria rather than by excess stomach acid, until and unless I have some (positive) rea-

son to believe that you might be lying or that you just are not in a position to know about

such things. Certainly we need to have some positive evidence for the general reliability

of testimony (i.e., we need to have inductive evidence for some relevant inductive gener-

alization in order for direct inference to even get off the ground); yet we cannot, on pain

of general skepticism about induction, require that the agent have positive reasons for

thinking that probabilities will not change for narrower reference classes. This approach

yields a principled reference class for inductive generalization and for direct inference:

the narrowest one for which the agent has adequate probabilistic information. This, then,

provides a solution to both (SPA i) and (SPA ii).

The consequence of all this is that if Coady wants to maintain this argument against

the Humean theory of testimony, he is going to have to view all induction as suspect.

Without something like the Reichenbachian principle, we are simply faced with the (old)

problem of induction. Coady's philosophy may be closer to Hume's than we had been led to believe.

V. Testimony and Folk Psychology

So far, I have argued that none of Coady's criticisms of the inductivist theory of testimo-

ny actually work. In particular, I argued that the necessary connections that may obtain

between truth and testimony and between truth and the learning of language are irrele-

vant to the question of whether our testimonial beliefs are justified via induction. I have

also argued that the Strong Paucity of Evidence Argument that Coady offers is too

strong, in that if it works against induction of testimony, it works against induction in

general. Yet this latter claim does not serve to refute the Weak Paucity of Evidence

Argument. This argument, I think, is the argument against an inductive theory of the jus-

tification of testimonial belief.

The central claim of WPA is that the number of reports that we have actually checked

is too small to justify us in our testimonial beliefs. The fact that so much of what we

believe we believe on the basis of testimony shows that correspondingly little of what we

believe could even possibly serve to justify induction. This argument, that any inductive

evidence for the reliability of testimony must be an argument from a small sample, can

neither be rendered a decisive argument against inductivism, nor can it be decisively

refuted until someone figures out how large a sample must be and how large of a sample

we actually are able to bring to bear in our inductive argument for the reliability of testi-

mony. I will not take this route. Instead, I want to lessen the force of WPA by showing

how we, as epistemic agents, might acquire additional bases of evidence for our belief in

the general reliability of testimony, bases that are overlooked by WPA. That is, I want to

try to show that the inductive sample may not be as small as WPA assumes it is.

The central weakness in WPA, I will argue, is that it presumes that whatever induc-

tive evidence we might have for the general reliability of testimony must be acquired by

checking reports against facts (e.g., perceiving that S says that p and perceiving that p).

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Jack Lyons 171

In what follows, I will try to enlarge the inductive base by arguing that we can also acquire inductive evidence for the reliability of testimony by inferring it from (non-testi-

monially) justified folk psychological beliefs. This, of course, raises the question of how

we acquire our folk psychological beliefs, since this is obviously relevant to how such beliefs are justified and whether they can play the role I want to assign them. To illus- trate the relevance of our folk psychological beliefs to testimonial justification, I will

examine in some detail one particular psychological and philosophical theory about the

origins of our folk psychological beliefs. I will then try to show how this theory, the sim-

ulation theory, improves the argument for an inductivist theory of the justification of testimonial beliefs.

The problem with Hume's treatment of testimonial belief is that it assumes that our

evidence for the reliability of testimony must come in the form of personally experienc-

ing a correlation between reports and facts (or at least things that are taken by the agent

to be facts). This is what Coady has in mind when he speaks of 'verifying reports'; we hear someone say that p and we find independent, non-testimonial evidence for p. All

that is sought here is a simple correlation between utterances and the world, without any attempt to get inside the minds of the testifiers.

However, the folk, whose testimonial beliefs are in question here, are not behav- iourists, and they (we) do not reason like behaviourists; in explaining and predicting

human behaviour, the folk do not appeal only to lawlike uniformities that obtain between

people's environments and their behaviour (between the facts and the reports), but also

to people's internal mental states. Our folk psychology is an explicitly mentatistic one. I

explain your dropping your car off at the brake shop in terms of your desire to have your brakes repaired and your belief that the shop in question will repair them. Not only do

my folk psychological beliefs enter into an explanation for me of your behaviour, how-

ever; these same beliefs also account for a lot of my behaviour. My beliefs about your

beliefs and desires constrain the ways in which I am willing to behave around you. Thus, in accounting for the justification for our belief in the general reliability of tes-

timony, it is implausible to think that simple fact-report correlations are the only kinds of

evidence we bring to bear on the issue. We, as epistemic agents, also have at our disposal

a wide range of folk psychological beliefs that we can use to support statistical general- izations that are relevant to our belief in the reliability of testimony. Furthermore, our

folk psychological beliefs are clearly relevant to our reliance on testimony in that they

account for the way in which we engage in direct inference. When trying to figure out whether to believe a particular report, we consider not only (not even primarily) the sort

of report being given; we also take into account the mental states of the person doing the

reporting (e.g., the speaker's possible motives for lying, the speaker's background expe-

rience, etc.). The folk psychological beliefs that are most relevant to the present topic are

(i) that people generally try to tell the truth (unless they have some motive to lie), and (ii)

that people are generally competent with respect to believing the truth. Call these beliefs

the Sincerity Principle and the Competence Principle, respectively. What needs to be

shown is that it is possible to have inductive justification for these two principles, evi- dence that is (a) not itself based on testimony (b) not justified by fact-report correlation

checking, and (c) derivable from justified folk psychological beliefs or the mechanisms that produce these justified beliefs.

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172 Testimony, Induction and Folk Psychology

I think it is fairly obvious how the Sincerity Principle and the Competence Principle,

if justified non-testimonially, provide evidence for the general reliability of testimony.

What needs to be shown is that these beliefs are susceptible to inductive, non-testimonial

justification. In the following section, I will focus on a particular psychological theory

about the origins of our folk psychological beliefs and how it could account for our

inductive evidence for our testimonial beliefs. I will try to show that this theory provides

some evidence for the claim that the Sincerity Principle and the Competence Principle

are justified via inductive generalization. Then I will show how this theory allows us to

use and modify these principles in direct inference.

VI. Simulation and Induction

There are numerous examples of folk psychological beliefs that, intuit ively, are

justified, l° Here are a few of mine: 'Fred bought that car because he wanted to have it',

or 'All the people in the room with me right now would say that they believe that the

lights are on if they were asked.' And a bit more to the point, 'People generally form

beliefs about the visual properties of their environments by using their eyes.' 'Every

American knows a toilet when she sees one and, for that matter, knows what the word

"toilet" means.' 'People do not generally lie unless they have some reason to do so.' I

classify all of these as folk psychological beliefs because they involve the ascription of

mental states to others, and it is beliefs like these by which the folk predict and explain

the behaviour of others. It is not only the content that makes these beliefs folk psycho-

logical beliefs; the previous beliefs count in part because I did not engage in any

empirical studies or rely on professional psychology to arrive at them. Furthermore, even

though reliability, for example, is not a mental state, to ascribe reliable belief forming

mechanisms is to make a claim about that person's psychological states. Thus I take

claims made by the folk about the truth and the justification of other people's beliefs to

fall under the rubric of folk psychology. This will be made more clear when I discuss the

details of the simulation theory.

To determine the source of the justification of these beliefs, we should look into the

source of the beliefs themselves. There are a number of psychological theories about the

origin of our folk psychological beliefs, and they fall into two main categories.

According to the simulation theory (see, e.g., [4], [5] and [7]), we form beliefs about the

mental states of others by using the mechanisms by which we form the corresponding

states in ourselves. We simply imagine ourselves in the other's position, and see what

states are produced; that is, we take our own mental state production mechanisms 'off-

l ine ' , feed in the relevant perceptual and other inputs, and simply introspect the

appropriate output. Being hit by an imaginary rock causes imaginary anger when I run

that input through my off-line mental state production mechanisms, so I predict of some-

one who has just been hit by a rock that she will be angry) 1

~0 Even if you think that belief-desire psychology is badly enough mistaken that it will not end up in a finished science of the mind, this does not at all preclude you from thinking that ordinary people are justified in their folk psychological beliefs (at least to some ordinary, non-scientific degree of justification).

" I am, of course, glossing over a number of subtleties that make the view more attractive. None of these subtleties will be relevant to the present discussion, however.

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Jack Lyons 173

How, then, would the simulation theory help inductivism? In section II, I claimed that

learning a language and learning that people's reports are generally accurate can take

place concurrently, and the consequent beliefs can be justified inductively (viz., abduc-

tively) even if Reid's principle of credulity is true. This would indicate that we have

done some first hand report checking, but what simulation can do is to give us further

evidence and expand on the inductive sample that WPA insists is too small by giving us

additional evidence for the Sincerity Principle and the Competence Principle. The role of

simulation is to provide the agent with a host of (justified) beliefs about single cases,

from which the agent can then induce the appropriate generalizations.

For instance, say I want to know whether Smith believes that there is a rhinoceros in

my living room. According to the simulation theory, I simply imagine myself in Smith's

position (sitting on my living room couch), feed the relevant perceptual inputs into my

(now off-line) mental state production mechanisms, and introspect whether these mecha-

nisms produce an ersatz belief that there is a rhinoceros in the room. Since they do not, I

conclude that Smith would not have this belief. Then I ask Smith to consider the proposi-

tion that there is a rhinoceros in my living room and simulate her understanding my

request and forming the belief that there is not one in the room. I conclude that Smith

believes that there is not a rhinoceros in the room. Here is one folk psychological belief

of mine (it involves a mental state ascription) that (I presume) is justified and that is cer-

tainly not indebted to testimony for its justification. Now since I am justified in believing

that Smith believes there is not a rhinoceros in the room (on the basis of simulation), and

I am justified in thinking that it is true that there is not one in the room (on the basis of

perception), I am justified in believing that at least one person has at least one true belief.

I perform many such simulations with different people, and end up with a number of

beliefs that support the inductive generalization that people are generally competent in forming beliefs.

Even though the above example involves my 'checking' Smith's belief in that I have

a justified belief that she believes p and an independent, justified belief that p, this still

constitutes an enlargement of the inductive sample mentioned in WPA, for Smith has not

said anything. Simulation offers a wider inductive sample than WPA assumes, because it

does not require us to check reports, since it does not require the existence of reports.

Simulation allows for belief checking without report checking. But simulation can do

more than this, for I do not even have to check each particular belief to be justified in

thinking it is true. Given that I am justified in thinking that I am generally competent in

my ability to form true beliefs, then the beliefs that I ascribe to people will be beliefs that

I would ascribe to myself if my situation were similar to theirs, most of which, by

hypothesis, I am justified in thinking are true. Given the ubiquity of such folk psycholog-

ical beliefs, it seems clear that the inductive sample, at least for the reliability of beliefs, must be a great deal larger than WPA supposes.

A similar story goes for the belief that people are generally sincere. If I am generally

sincere, then, ceteris paribus, I will make many individual ascriptions of sincerity to var-

ious people. And given that most of my folk psychological beliefs are justified, I will

have a wide sample of justified beliefs in the sincerity of people, from which I can

induce that people are generally sincere. So provided that I am generally sincere, and

provided that I justifiably believe that I am generally competent, simulation combined

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174 Testimony, Induction and Folk Psychology

with inductive generalization will provide me with inductively justified beliefs that peo-

ple are genera l ly competen t and genera l ly sincere. Even i f I am ep is temica l ly

incompetent, this incompetence is going to infect my third-person belief ascriptions in

just the way that it infects my own beliefs, thus giving me evidence that people form the

correct (by my own dim lights) beliefs? z

This is just a sketch, but if what I am claiming is right and if the simulation theory is

true, then the evidence that we have for the competence and sincerity of others is, indeed,

justified via induction, since it is inductive generalization that produces the general

beliefs in the first place. The way simulation works is by producing first a belief in me

about your mental states, then one about my sister's mental states, and so on. Simulation

thus produces only particular beliefs, not general ones, so the generalizations cannot be

the direct output of the simulation mechaflism. Apparently, if the simulation theory is

right, then whatever generalizations we believe must be inductively justified if they are

justified at all. Thus, whatever justified particular testimonial beliefs we come to have by

relying on these general beliefs will be inductively justified. In virtue of what are the par-

t icular simulated beliefs jus t i f ied? It does not matter very much for the present

discussion; so long as they are in fact justified, it is irrelevant whether you want to say

that this is because the faculty that produces them is reliable or innate, or whether you

think that simulation only provides hypotheses to await abductive testing. '3 In more para-

digmatic cases of induction, the particular beliefs from which the statistical or universal

generalizations are inferred are typically justified on the basis of sense perception, hut

we need not commit ourselves to a theory of perceptual justification in order to claim

that these generalizations are inductively justified. All that is relevant here is whether,

not how, the particular beliefs are justified (so long, in the present case, as they are not

justified via testimony, which they pretty obviously are not). So all that matters here is

that the beliefs we form on the basis of simulation are generally justified, and I doubt

that anyone wants to deny this, at least not that they are justified in some ordinary, every-

day sense, which is all that is at issue here.

Thus we see two very different ways in which an agent can come to be justified in the

claim that most people are reliable in their reports. The first is the way that Hume and

Coady recognise: I see that S says that p and p, and I see that R says that q and q, and so

forth. Eventually, I acquire some inductive evidence for the claim that people are gener-

ally reliable from this procedure of checking reports against facts. When we take into

consideration our body of justified folk psychological beliefs, however, we find an addi-

tional, independent source of justification for the belief that people are generally reliable

in their reports, for belief is a straightforward inference from the (inductively justified)

Sincerity Principle and Competence Principle. This is the sense in which I have been

claiming that the inductive base is broader than what WPA is willing to admit; the cen-

tral claim of WPA is that checking reports against facts does not provide enough

,2 This argument only flies if the epistemic agent in question is justified in believing herself to be generally competent and is generally sincere. So all bets are off when it comes to pathological liars and people who are not justified in thinking they are competent. This does not strike me as a problem for the present theory, since it is not at all obvious that such people are justified in their testimonial beliefs.

,3 The view that reliability justifies the particular beliefs is suggested in [4]. The abductive story, I presume, will simply be an analogue of the one I sketched in section II.

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Jack Lyons 175

evidence to justify our reliance on testimony. The claim here is that even if WPA is right

on that count, it does not matter, since there are additional sources of justification for our

belief that people are generally accurate in their reports. TM

In addition to serving as the basis for inductive generalization, simulation can help

with direct inference. It can do this by explaining how we come to have positive reasons

for moving to a narrower reference class. As the discussion in section IV indicates, if we

do not have a positive reason to think that the particular instance at hand deviates from

the general case, we are justified in inferring that the definite probability is pretty much

the same as the indefinite probability. Direct inference, then, involves searching for rea-

sons to th ink that the case at hand is s ignif icant ly different f rom the general case.

Suppose, for example, that Jones tells me that p. Assuming that I am justified in thinking

that people generally do not lie, then I am justified in believing p unless simulation indi-

cates that Jones may be lying (assuming I have no other information concerning p). I

simply imagine myself in Jones' situation and introspect whether I would be tempted to

lie. If I think I would be, then I should not believe p on the basis of Jones' saying so.

Similarly, suppose that you tell me that q, and I do not have any reason to think that

you are lying. Even though I am justified in thinking that you are sincere, you may not

be competent with respect to q. If I am justified in thinking that people are generally

competent, then I am justified in believing that you are, too, unless simulation indicates

otherwise. I imagine that q is true, I imagine myself in your situation, and I introspect

whether q would be obvious to me in your situation, and I repeat the process, only this

time imagining that p is false. If I cannot tell the difference, I wilt doubt that you can.

This should work whether projecting myself into your situation means imagining that I

am standing in the other room or imagining that I have just spent a year and a half study-

ing the grooming habits of the Yellow-Footed Albatross. While this is nothing like a

complete theory of direct inference, it does indicate the role that simulation is capable of

playing.

This concludes my sketch of how the inductivist might resort to the simulation theory

in order to avoid the Weak Paucity of Evidence Argument. The simulation theory is par-

ticularly well-suited to an inductivist theory of testimony, as the role of simulation is to

provide to the agent who is doing the simulating a range of (intuitively, justified) particu-

lar beliefs about the mental states of others, from which can be induced generalizations

about people's belief-forming mechanisms and their reliability as well as generalizations

One anonymous referee has suggested that there is a sense in which the inductive base provided by simulation is really as small as WPA suggests and that what the simulation theory does is to explain how such a small base can do so much justificational work. According to this referee, simulation 'gives us a very narrow "base" but enables us to recursively generate a huge expanse of conclusions from that narrow base'. We are justified in trusting our simulator, and this justifi- cation allows us to generate justified folk psychological beliefs. In the end, however, all of this higher-level justification (for our particular beliefs about people) rests on the lower-level justifi- cation for the principle 'trust your simulator', and it is in this sense that our higher-level justification rests on a surprisingly narrow base. This is a very interesting point, and it may be right, but this is not how I intend my claim that simulation broadens the inductive base. For the present purposes, I am merely trying to show that our folk psychological beliefs, whatever the ultimate source and structure of their justification, can and most likely do supplement the justifi- cation we obtain by checking reports against facts. So at least at this higher level, simulation does provide a broader inductive base from which to justify our reliance on testimony. This claim is all that is really needed to undermine WPA.

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176 Testimony, Induction and Folk Psychology

about people's motives and consequently about their sincerity. In fact, if the simulation

theory is true, it seems quite obvious that our beliefs in statistical generalizations about

folk psychological matters must be the product of inductive generalization over a range

of simulation outputs? ~ And if I am right in insisting that our folk psychological beliefs

enter into belief in the general reliability of testimony, then it seems very reasonable to

hold an inductivist theory of testimony.

Most importantly, if simulation produces justified beliefs about the mental states of

others (as presumably it does if the simulation theory is true), then we can gather an

inductive sample (i.e., a set of justified particular beliefs from which to infer statistical

generalizations) without having to check individual reports. In this way, the inductivist

can avoid the WPA by expanding the agent's fund of first-hand experience of checking

reports, adding to it a pool of simulated experience.

VII. Concluding Comments

The goal of this paper has not been to show that inductivism is inevitable, but to show

that one set of arguments against it is unconvincing. One of the more interesting flaws in

the arguments against inductivism, I have tried to show, is a failure to appreciate the role

of our folk psychological beliefs in the justification of our testimonial beliefs. I have

argued that the simulation theory supports an inductivist position concerning the justifi-

cation of our testimonial beliefs. I have focused on the simulation theory party because it

is a plausible theory, partly because it is friendly to inductivism, and partly because I

needed some theory to focus on for the sake of illustration. If nothing else, I hope it has

become clear that the nature of our folk psychological beliefs is relevant to the debate

concerning the nature of testimonial justification. Still, it is worth noting that the alterna-

tives to the simulation theory do not necessarily cut against an inductivist view of

testimony.

The only going competitor to the simulation view is what is called in cognitive scien-

tific circles the 'theory theory' (see, e.g., [6] and [12]), which, as I will use the term, is

merely the claim that our folk psychological beliefs are derived from a tacit theory we

possess concerning human psychology. The theory theorist must claim that our beliefs in

the sincerity and the competence of others are either learned or innate parts of this theo-

ry.~6 1 argued in section II that innateness does not speak to the issue of justification; it is

quite possible for the beliefs to be innate and still abductively justified. If, on the other

hand, the Sincerity Principle and the Competence Principle are learned, then presumably

they are either induced or are learned via testimony. Surprisingly, even in this case, the

inductivist need not concede defeat, for what is at issue is the just i f icat ion of these

beliefs, not merely their origin, and it is hard to see how testimony could justify me in

~5 Contra Stich and Nichols [12], the debate between the simulation theorist and the theory theorist is not about whether people possess folk psychological theories. The generalizations I am rely- ing on constitute a theory, insofar as any set of generalizations does. What is at issue is the nature of that theory and the role it plays in mental state ascription. The simulation theory must admit that we do have folk theories; it is just that we do not (always) use these theories to make third-person mental state ascriptions.

~6 According to Fodor [3], the whole theory is innate, afortiori these beliefs must be innate. Paul Churchland, on the other hand [1], claims that the theory is learned, these two beliefs included, presumably.

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Jack Lyons 177

believing these two principles. The fact that you tell me that you .are sincere is not suffi-

cient to justify my belief in your sincerity. Perhaps your saying so makes me consider the

hypothesis and subsequently subject it to test, but in that case, it is no longer really a tes-

timonial belief. Any genuinely testimonial support for the Competence Principle or the

Sincerity Principle would be hopelessly circular. If these beliefs are justified, then they

must be inductively justified on this version of the theory theory, so the theory theory is

at least compatible with inductivism.

This does not imply that our position concerning testimonial justification is indepen-

dent of our position concerning simulation and the theory theory. On the contrary, the

simulation theory offers a strong argument against WPA in virtue of enlarging the induc-

tive sample and a strong positive argument in favour of inductivism in that simulation

only gives us particular beliefs, so that the formulation of general beliefs will require

inductive generalization. The theory theories give us neither of these arguments, at least

not as obviously as the simulation theory does. Thus the cognitive scientific debate con-

cerning the mechanisms underlying third-person mental state ascription is extremely

relevant to the philosophical debate concerning the status of testimony.

I hope that the general approach embodied here, combined with a number of the par-

ticular claims, suggests that the project of accounting for our justified testimonial beliefs

is better pursued by leaning on psychology than by leaning on the philosophy of lan-

guage - I have tried to show that the arguments that Coady borrows from the philosophy

of language are unsuccessful and that the outcome of a cognitive scientific debate will

have an effect on the plausibility of inductivism. The basis on which we believe testimo-

ny is at least partly an empirical issue; it would be odd if we could resolve this issue by

the use of a priori arguments. It is not yet clear whether the simulation theory or some

version of the theory theory is going to turn out to be right (or perhaps something not yet

thought of). Certainly there are important theoretical considerations that bear directly on

these views, but there is also a lot of empirical work in cognitive development yet to be

done that will be very relevant to this project. Yet, despite this present uncertainty, I

think that the foregoing offers some reasons to be optimistic about an inductivist theory

of testimonial justification.~7

University of Arizona Received March 1996

Revised August 1996

'~ Thanks to Alvin Goldman, the University of Arizona Epistemology Reading Group, and three anonymous referees for helpful comments on earlier drafts of this paper.

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178 Testimony, Induction and Folk Psychology

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119. 6. A. Gopnik, 'How We Know Our Minds: The Illusion of First-Person Knowledge of

Intentionality', Brain and Behavioral Sciences 16 (1993) pp. 1-14. 7. R.M. Gordon, 'Folk Psychology as Simulation', Mind and Language 1 (1986) pp. 158-171. 8. J.L. Pollock, Nomic Probability and the Foundations of Induction (Oxford: Oxford University

Press, 1990). 9. H. Reichenbach, A Theory of Probability (Berkeley: University of California Press, 1949). 10. T. Reid, Philosophical Works (ed.) William Hamilton (Hildesheim: Georg Olms

Verlagsbuchhandlung, 1967 [1764]). 11. E. Sober, Core Questions in Philosophy (Englewood Cliffs, NJ: Prentice Hall, 1995). 12. S. Stich and S. Nichols, 'Folk Psychology: Simulation or Tacit Theory?', Mind and Language 7

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